Vrftsjtryk

Explain breifly about chandas and abhimany devthas

like for gaythri mantra its gaythri chands, savitha devaatha rshi is vishwa mitra

one chandas how many letters how one should refer or add for missing letters in chandas while doing yagya

Vedic meter or Chanda" (छन्द ) points towards how a mantra or verse is constructed in some definite rules.. A Chandas is having rule of how many letters are there in it and how theese letters are divided into different parts called Paadas .
Chandas is one among six Vedangas or parts of Vedas.

There are a number of Chandas used in Vedas , Mainly there are Seven Chandas used in Vedas and those are are:

Gayatri: This Chandas has 24 Letters/Aksharas in each stanza/mantra divided into 3 Paadas (parts/legs) of 8 Letters/Aksharas.

Examples of Gayatri Chanda.:-

Gayatri Mantra

Ushnik : This Chandas has 28 Letters/Aksharas in each stanza/mantra divided into 4 Paadas of 7 Letters/Aksharas

Anustup: This Chandas has 32 Letters/Aksharas in each stanza/ mantra divided into 4 Paadas of 8 Letters/Aksharas. Most of the Slokas in typical classical Sanskrit uses this Chandas, most often recited being.

Example of Anustup Meter -:

Brihati : This Chandas has 36 Letters/Aksharasin each stanzas or mantra divided into four 4 Paadas (8 + 8 + 12 + 8) Letters/Aksharas.

Pankti : This Chandas has 40 Letters/Aksharas in each stanza divided into 4 Paadas of 10 Letters each (sometimes 5 Padas of 8 letters each)

Tristup: This Chandas has 44 Letters/Aksharas in each stanza divided into 4 Paadas of 11 Letters/Aksharas.

Jagati: This Chandas has 48 Letters/Aksharas in each stanza divided into 4 Paadas of 12 Letters/Aksharas.

Here is Information about Chandas / Upa chandas , sub meters used in Rig-Veda.
Link 1
Link 2

Anustupa अनुष्टुप्
क. -कविराट अनुष्टुप् Kaviraat Anustupa , ख - कृति अनुष्टुप् kruti Anustupa , न -नष्टरूपी अनुष्टुप् Nastarupi Anustupa , घ - विराट अनुष्टुप् Virat Anustupa.

उष्णिक Ushnika
क. - अनुष्टुप् गर्भा उष्णिक Anustupa Garbha Ushnika , ख - ककुप उष्णिक Kakupa Ushnika , ग - तनुषिरा उष्णिक Tanushira Ushnika , घ - पुर उष्णिक Pur Ushnika

गायत्री Gayatri
क - द्विपदा विराट गायत्री Dwipada Virat Gayatri , ख - पाद् निचृत् गायत्री Pada Nichrut Gayatri , ग - प्रतिष्ठा गायत्री Pratistha Gayatri.

जगति Jagati
क - महापन्क्ति जगति Mahapankti Jagati

त्रिष्टुप् Trishtupa
क - महाब्रुहति त्रिष्टुप् Mahabruhati Trishtupa , ख - यवमध्या महाब्रुहति त्रिष्टुप् Yavamadhya Mahabruhati Trishtupa.

पंक्ति Pankti
क - चतुष्पदा विराट पंक्ति Chatuspada Virat Pankti , ख - प्रस्तार पंक्ति
प्रगाथ pragatha

बृहती Bruhati
क -विष्टार बृहती बृहती Vishtaar Bruhati Bruhati , ख - स्कन्धोग्रीवी बृहती skandhogrivi Bruhati
AtiShakvari - अतिशक्वरी , Atijagati अतिजगति

Major metres

The major Chandahs are 7 in number. They are - Gayatri, Ushnik, Anushtup, Brihati, Pangkti, Trishtup and Jagati.

Sometimes Pangkti is also called Virat.

The number of syllables or Aksharas in the Mantra determine to which Chandah (or metre) it belongs to.

Given below are the distribution, variants and total number of Mantras (for a particular Chandah in the Vedas):

Chandah name - Distribution - Number of variants it has - total number of mantras
that are in this particular Chandah

Gayatri - 8|8|8 - 10 - 2456
Ushnik - 8|8|12 - 7 - 398

Anushtup - 8|8|8|8| - 7 - 850
Brihati - 8|8|12|8 - 11 - 427

Pangkti - 8|8|8|8|8 - 7 - 499
Trishtup - 11|11|11|11 - 14 - 4258

Jagati - 12|12|12|12 - 3 - 1353.

So, while Gayatri Chnadah will have 24 syllables, Anushtup 32 syllables, a Pangkti Chandah will have 40 syllables and so on.

The Chandah called Pangkti-Virat has 40 aksharas (syllables) and it's distribution is 10|10|10|10.

But for Gayatri there are as many as 10 variants and not all of them have exactly 24 syllables.

Minor metres

There are some minor Vedic metres as well like Atijagati, Dhriti, Ati Dhriti etc. A similar list for them is as given below:

Atijgati - 12|12|12|8|8 - 17
Shakvari - 8|8|8|8|8|8|8 - 19

Atishakvari - 16|16|12|8|8 - 10
Ashith - 16|16|16|8|8 - 7
Atyashith -
12|12|8|8|8|12 - 82
Dhriti - 12|12|8|8|8|16|8 - 2

Source - Essentials of Rig Veda, R.L.Kashyap ( Sri Aurobindo Kapaly Shastry Institute of Vedic culture).